Early inter-hospital transfer of patients with myocardial infarction without a doctor, paramedic or nurse on board: results from a French regional emergency care network

Urgent percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) and early revascularization for non-ST-segment elevation myocardial infarction (NSTEMI) are recommended in international guidelines [1, 2]. The main factors limiting the implementation of these recommendations are the geographic availability and the capacity of centres with cath-labs (PCI centres). One solution would be to shorten the stay of patients in PCI centres (i.e. transfer them between remote hospitals without cath-labs and PCI centres before/after the invasive procedure).

In France, following acute treatment, patients with STEMI remain in the PCI centre for 48 h before transfer. Patients with acute NSTEMI are transferred between hospitals in mobile intensive care units (MICUs), which have on-board medical/paramedic teams [3]. As both groups of patients are generally considered to be at high risk during this period, they require transfer with a doctor and nurse on board. Paul et al. [4] reported a high incidence of complications during the transportation of high-risk patients (i.e. within 12 h of acute STEMI and 24 h of complicated NSTEMI), justifying transportation with doctors on board, whereas Bawejski et al. [5] reported a low incidence of complications during the transportation of patients within 24 h of uncomplicated NSTEMI. Therefore, it may be possible to reassess the patients’ individual risk levels and adapt the type of transfer (i.e. with or without medical/paramedical staff) accordingly.

Four studies have reported on the safety of early transfer of patients with acute coronary syndromes (ACS) between remote hospitals and PCI centres [6‐9]. These transfers were, however, conducted with doctors [6, 7] or nurses [8] on board and often involved low-risk patients (i.e. with unstable angina) or excluded high-risk patients with STEMI [8, 9]. The safety of return transfers of STEMI patients to remote hospitals within 48 h of their admission to the PCI centre, and the early round-trip for patients with NSTEMI within 72 h of their admission to a remote hospital, without doctors or nurses on board, remains questionable.

In our region of France, intermediate-risk ACS patients can be transferred from a remote hospital to the PCI centre (NSTEMI patients only) and back to the remote centre after PCI (NSTEMI and STEMI patients) using the ‘SCA-Alp’ protocol. This involves an ambulance equipped with an automatic external defibrillator, driven by a driver with specialist training in basic life support, but without a medic or paramedic on board. Further, patients are returned to the remote hospital within 12 h (NSTEMI) or 24–48 h (STEMI) of PCI, rather than the standard 48 h. The aim of this retrospective, observational study was to report clinical outcomes in such patients transferred using the SCA-Alp protocol.

This was a retrospective, observational study on early transfer (without doctors or nurses on board) of intermediate-risk patients with NSTEMI or STEMI between one of seven remote hospitals in the Haute-Savoie department in France and one PCI centre.

The Haute-Savoie department is a mountainous area with approximately 800,000 inhabitants in 2015 [10]. One PCI centre (Annecy hospital) collaborates with four remote hospitals that have intensive care units (ICUs) and a MICU team and three hospitals/clinics without ICUs or a MICU team (Fig. 1). Two remote hospitals with ICUs and MICU teams (Chambéry and Albertville), located outside the Haute-Savoie department, collaborate partially with the PCI centre. The PCI centre has two cath-labs and four on-call interventional cardiologists. Eight beds are available exclusively for pre- and post-coronary intervention monitoring in a room located close to the cath-lab from 8 am to 8 pm.

In this geographic area, the RESeau des URgences CORonaires (RESURCOR) network is a coordinated regional system of care for patients with cardiac emergencies, and forms part of REseau Nord Alpin des Urgences (RENAU). The RESURCOR network disseminates protocols via pocket cards and booklets, available at a dedicated website (www.​renau.​org). An ongoing regional prospective registry of STEMI patients has provided data since 2002 on the acute phase of patient care [11‐15].

One of the protocols of the RESURCOR network – the SCA-Alp protocol (Fig. 2) – is used to implement early transfers from remote hospitals to and from the PCI centre for intermediate-risk patients with acute NSTEMI; and early return transfers from PCI centres to remote hospitals for intermediate-risk patients with acute STEMI. SCA-Alp transfers occur in private ambulances with two basic life support-trained drivers on board and equipped with an automatic defibrillator, but without heart rhythm monitoring. Prior to the introduction of the SCA-Alp protocol, high- and intermediate-risk patients would have been transferred by MICU, with low-risk patients being transported by regular ambulance; and patients would have remained in the PCI centre for 48 h after PCI.

Patients with NSTEMI who have been admitted to an ICU in a remote hospital are transferred according to the SCA-Alp protocol to the PCI centre within 24–72 h (Fig. 2; Table 1). Patients are only eligible for SCA-Alp transfer (instead of by MICU) from the remote hospital to the PCI centre if they had been stable for at least 24 h in the remote centre (i.e. no acute cardiac failure condition, no underlying ventricular arrhythmia, and no ST-segment depression > 3 mm in ≥2 leads). Patients who underwent PCI were only eligible for SCA-Alp transfer back to the remote centre within 12 h of the procedure if the PCI result was optimal. Otherwise, they remained in the PCI centre.

Patients with STEMI diagnosed in a remote hospital are transferred straight to the PCI centre in a MICU, where a primary or rescue angioplasty after thrombolysis may be performed (Fig. 2; Table 1). After PCI, intermediate-risk patients are transferred back to the remote hospital (closest to the patient’s home) within 24–48 h using a SCA-Alp transfer. This only applies to patients with an optimal revascularization procedure and no recurrence of angina, acute cardiac failure, or significant ventricular arrhythmias in the 24 h following admission. High-risk STEMI patients (i.e. non-optimal revascularization, recurrence of angina, acute cardiac failure, or significant ventricular arrhythmias within 24 h after PCI) remain at the PCI centre.

Low-risk patients who are returned to the remote hospital > 48 h after PCI are not eligible for the SCA-Alp protocol. Instead, they are discharged or transferred back to the remote hospital by regular ambulance.

During the study period, 1172 patients with STEMI were treated in the Annecy PCI centre. Of these, 602 patients were transferred immediately (via MICU) from the emergency department at a remote hospital to the PCI centre (n = 225) or arrived after initial treatment in a MICU (from home) from a remote area (n = 377). Just over half (54.0%) were treated with thrombolysis and 36.9% were admitted for primary PCI. One hundred and one of these patients were returned to their remote hospital using the SCA-Alp protocol within 48 h (Fig. 3a).

During the same period, 1968 patients with an initial diagnosis of NSTEMI were transferred from a remote hospital to the Annecy PCI centre, of which 867 were transferred using the SCA-Alp protocol and transferred back within 12 h. A total of 490 patients initially stayed < 72 h in the remote hospital before transfer to the PCI centre and were transferred back using the SCA-Alp protocol within 12 h (Fig. 3b) (198 patients were transferred within 24 h, 168 between 24 and 48 h, and 124 between 48 and 72 h).

Patient baseline characteristics, initial management, and angiographic characteristics are detailed in Tables 2 and 3. All patients were treated with a P2Y₁₂ inhibitor before arrival at the cath-lab. Access was radial for most patients (94.6%).

Ten of the 43 patients with STEMI admitted for an emergency angiogram and without previous fibrinolysis did not undergo PCI: four of these patients had a very narrow infarct-related artery (three had a final TIMI flow of 0 and one had a final TIMI flow of 2) and six had an initial TIMI flow of 3 and a non-significant lesion and/or the artery was too small to be dilated. Table 4 shows the initial TIMI flow distribution of the 43 patients admitted for an emergency angiogram without previous fibrinolysis and the final TIMI flow of the 82 patients treated with PCI (33 primary PCI, 20 rescue PCI after failed thrombolysis, and 29 treated with delayed PCI after successful thrombolysis).

Most patients with STEMI (90/101, 89.1%) or NSTEMI (467/490, 95.3%) were transferred from or to the four main remote hospitals with an ICU. The mean maximum troponin concentration among NSTEMI patients was 1.69 ± 7.8 μmol/L and the overall mean length of hospitalization in the remote hospital was 5.0 ± 3.2 days.

This retrospective study shows the feasibility of a protocol for early return to a non-interventional hospital after PCI for selected intermediate-risk patients with an ACS. No adverse events occurred during transportation without doctors or nurses on board during return transfer 24–48 h after PCI of patients with STEMI or for same-day round trips for patients within 24–72 h of NSTEMI. No deaths were reported and only two of 591 patients needed to be transferred back to the PCI centre within 48 h (in a MICU) for another PCI due to stent thrombosis. The SCA-Alp approach frees up beds in PCI centres, which are in increasing demand. Performing these transfers without doctors or nurses on board allows a more streamlined use of medical facilities, but requires a well-organized system with well-targeted patients, shared protocols and trained staff, as followed in our SCA-Alp protocol.

Comparison of our results with previous reports on early return transfers is difficult due to the heterogeneity in the risk level of ACS patients. Some studies have included high-risk patients with acute STEMI [4, 6, 7], while others have included lower-risk patients with NSTEMI > 72 h previously or unstable angina [8, 9]. Also, some transfers were performed with doctors or paramedics on board and others without. However, our results are concordant with these reports regarding the risk of stent thrombosis (0–2.2%) and in-hospital death (0–3.2%) [6‐9].

As MICUs are few in number and expensive, we hypothesised that many high-risk patients might be classified as being at intermediate risk for inter-hospital transfer, and hence be suitable for SCA-Alp transfer. We can define high-risk patients as those with acute STEMI, complicated patients, and those who have had an uncomplicated STEMI or NSTEMI within the last 24 h. Such patients require MICU transportation. Low-risk patients are those with uncomplicated STEMI > 48 h ago or uncomplicated NSTEMI > 72 h ago. Intermediate-risk patients can therefore be defined as those with uncomplicated STEMI within the last 24–48 h or uncomplicated NSTEMI within the last 24–72 h. The results of our study suggest that these patients can be safely transferred using a protocol such as SCA-Alp. The risk level of patients with uncomplicated NSTEMI within the last 24 h is unclear, but they may be considered at intermediate risk, as Bawejski et al. [5] reported no complications requiring medical intervention among 93 such patients transported with doctors or nurses on board. Moreover, despite our protocol criteria, 198 patients with NSTEMI were transferred within 24 h by SCA-Alp in our study, without any reported complications. Of course, risk levels may be better defined using scoring systems such as the Global Registry of Acute Coronary Events (GRACE) [16]. This may provide a better risk estimation, and the use of GRACE could be examined in a future study.

Our approach addresses an important public health issue as most of our patients came from remote areas (602/1172 [51.3%] STEMI and 1968/2554 [77.1%] NSTEMI), and there are not enough doctors to perform such MICU transfers. The SCA-Alp protocol is based on a strong network and shared practices regarding cardiovascular diseases in our region.

Reocclusion occurred in two of our patients, one of whom was treated with bivalirudin, which increases the risk of acute stent thrombosis [17, 18]. Our inclusion period was also transitional in terms of antiplatelet therapy, and perhaps these stent thromboses would have been avoided with the use of the newest P2Y₁₂ inhibitors, ticagrelor and prasugrel. Indeed, PCI techniques continue to evolve and the intervention is becoming safer, allowing earlier return of patients, with almost systematic use of radial access for the coronary angiogram (> 94%), which is known to reduce bleeding risk [19].

The results of this retrospective observational study suggest that the early transfer of intermediate-risk ACS patients between PCI centres and remote hospitals – without doctors, paramedics, or nurses on board – is feasible, and is associated with low event rates.